A liquid crystal display device typified by a liquid crystal display panel, a liquid crystal display module and so forth utilizes optical anisotropy, dielectric anisotropy and so forth which are possessed by a liquid crystal compound (a liquid crystal compound means in this invention a generic term for a compound having a nematic phase, a smectic phase and so forth, and a compound having no liquid crystal phases but useful as a component of a liquid crystal composition.). As operation modes of this liquid crystal display device, a variety of modes are known, such as a PC (phase change), TN (twisted nematic), STN (super twisted nematic), BTN (bistable twisted nematic), ECB (electrically controlled birefringence), OCB (optically compensated bend), IPS (inch-plane switching), VA (vertical alignment), or PSA (Polymer sustained alignment) mode.
It is known that among these operation modes, the ECB, IPS, VA modes and so forth are utilizing a homeotropic property of liquid crystal molecules, and that a limited-viewing angle which is a disadvantage of conventional display modes such as the TN and STN modes can be improved especially by use of the IPS and VA modes.
A large number of liquid crystal compounds in which hydrogen at the lateral position on the benzene-ring is replaced by fluorine have been studied until now as components for a liquid crystal composition having a negative dielectric anisotropy which is usable to the liquid crystal display device with these operation modes (For example, refer to the patent documents Nos. 1 to 5 or the non-patent documents Nos. 1 and 2.).
For example, the patent document No. 1 or the non-patent document No. 1 shows a three-ring compound such as formula (ref. 1) or formula (ref. 2). This compound has a range exhibiting liquid crystal phases (a mesophase range) that is narrow, and a clearing point that is low when used for a liquid crystal composition.
The patent document No. 2 shows a four-ring compound such as formula (ref. 3). However, the dielectric anisotropy of this compound is not sufficiently large negatively.
The patent document No. 3 shows a four-ring compound such as formula (ref. 4) or formula (ref. 5). However, a clearing point is low when this compound is used for a liquid crystal composition.
The patent document No. 4 shows a four-ring compound such as formula (ref. 6). However, the dielectric anisotropy of this compound is not sufficiently large negatively.
The patent document No. 5 shows a four-ring compound such as formula (ref. 7). However, the dielectric anisotropy of this compound is not sufficient large negatively.
The non-patent document No. 2 shows a four-ring compound such as formula (ref. 8). However, this compound has a range exhibiting liquid crystal phases (a mesophase range) that is narrow, and a clearing point that is low when used for a liquid crystal composition. Furthermore, the dielectric anisotropy has a positive value instead of a negative one.

The patent documents cited herein are No. 1: German Patent 3,906,058 C; No. 2: WO 89/08687 A; No. 3: WO 89/08689 A; No. 4: JP 2002-193853 A; and No. 5: German Patent 10,136,751 A (2002). The non-patent documents cited are No. 1: Liquid Crystals (1994), 16 (4), 625-641 and No. 2: Liquid Crystals (2004), 31 (8), 1151-1158.